Abstract
BACKGROUND: A newborn was diagnosed by echocardiogram with an asymptomatic cardiac mass in the right ventricle after a systolic cardiac murmur was detected at birth. CASE PRESENTATION: Nine days after birth, the newborn presented with three syncopal episodes and oxygen desaturation which required resuscitation. The mass induced a complete right ventricular outflow tract obstruction. The presence of a patent foramen oval and a patent ductus arteriosus explained the absence of symptoms at birth. Surgery was rapidly considered since the situation was life threatening. The tumor was successfully resected. The mass was a mature teratoma confirmed by microscopic examination, illustrated by pictures and video. CONCLUSIONS: This case was unique because of the absence of symptoms in the first 9 days of the newborn's life even though symptoms should have mounted due to the obstruction postpartum. The delay was correlated to the closure of the patent ductus arteriosus. It is recommended that newborns with any cardiac mass be followed up regularly due to hemodynamic changes at birth.